This project involves the development of a new non-invasive approach for imaging oxygen consumption in the brain. This new approach combines the advantages of magnetic resonance spectroscopy, which can separate signals from different metabolites in the brain, and magnetic resonance imaging, which can localize signals to well-defined regions of the brain. If 17O-labelled oxygen is inhales, 17O NMR spectroscopy can separate and quantitate signals from 17O-labelled water, which is the end product of oxidative metabolism in the brain. The rise of this signal directly gives the rate of oxygen consumption in the brain. If this signal is imaged, the rate of oxygen consumption in different regions of the brain can be determined. At the present time, the spatial resolution of the approach is 0.8 cc. One of the major advantages of the 17O NMR approach is that NMR techniques are non-invasive, and can be used with humans, and that 17O-labelled compounds, i.e., oxygen and water, are non-radioactive, and non-toxic.